The invention relates to a method of producing activated carbon based on lignite [brown coal].
The production of activated carbon from lignite is known. Such known methods are described in the following documents:
D. J. McCarthy, Carbon 15 (1977), pp. 95-101.
Lignite is dried and briquetted. The lignite briquettes are comminuted again and activated with water vapor in a countercurrent.
R. A. Durie et al, Fuel 58 (1979), pp. 472-476.
The lignite is subjected to an acid washing and an ion exchange, dried in air, optionally granulated, carbonized and activated with water vapor.
L. J. Harner et al., Proc.-Int. Conf. Coal Res. 5th, 1980, 805-19/CA 90: 74826Y.
The lignite is predried to a moisture content of approximately 16% by weight and briquetted. The briquettes are comminuted again, carbonized and activated with water vapor.
A. Albiniak et al., Pr. Nauk. Inst. Chem. Technol. Nafty Wegla Politech. Wroclaw 41 (1985) 213-8 / CA 104: 209 764 n.
The lignite is dried, coked and subsequently activated with water vapor, carbon dioxide and oxygen.
DE-OS 36 03 003.
The lignite is dried, pyrolized at 350.degree.-500.degree. C. and activated with water vapor at 700.degree.-800.degree. C.
DDR-PS 207 183.
The lignite is dried to a moisture content of 20%, extracted with organic solvents, dried in air, subsequently mixed with sawdust and zinc chloride solution, granulated and heated to 600.degree.-750.degree. C.
DDR-PS 211 331.
The lignite is predried, mixed with sawdust and/or peat as well as hydrochloric zinc chloride solution, granulated and heated to 650.degree.-750.degree. C.
DDR-PS 227 946.
The lignite is dried and pressed to blanks, the blanks are comminuted, the comminuted blanks are finally pressed to blanks again, the finally-pressed blanks are degassed, comminuted and activated in known activating reactors.
EP-PS 2275 and EP-PS 2674.
The lignite is subjected to an acid and water washing, dried, ground and briquetted. The briquettes are comminuted, carbonized (at a low temperature) and activated.
Kirk-Othmer, Encyclopedia of Chemical Terminology, 3rd Edition, Vol. 4, pp. 561-569, "Activated Carbon" also describes some prior art methods of processing lignite into activated carbon.
These prior art references show the background methods and are herein incorporated in their entirety.
The known methods have the disadvantage that numerous method steps are required, for example, water and acid washing, drying, grinding, briquetting and coking of the lignite are necessary as a pretreatment of the lignite.